Combustion behavior, emission characteristics of SO2, SO3 and NO, and in situ control of SO2 and NO during the co-combustion of anthracite and dried sawdust sludge

Zili Zhang; Qinda Zeng; Runlong Hao; Hongzhou He; Fan Yang; Xingzhou Mao; Yumin Mao; Peng Zhao

doi:10.1016/j.scitotenv.2018.07.286

Combustion behavior, emission characteristics of SO₂, SO₃ and NO, and in situ control of SO₂ and NO during the co-combustion of anthracite and dried sawdust sludge

Sci Total Environ. 2019 Jan 1:646:716-726. doi: 10.1016/j.scitotenv.2018.07.286. Epub 2018 Jul 25.

Authors

Zili Zhang¹, Qinda Zeng², Runlong Hao³, Hongzhou He⁴, Fan Yang⁵, Xingzhou Mao⁵, Yumin Mao⁵, Peng Zhao⁵

Affiliations

¹ Fujian Special Equipment Inspection and Research Institute, Fuzhou 350008, Fujian, PR China; Xiamen University, Xiamen 361000, Fujian, PR China.
² Fujian Special Equipment Inspection and Research Institute, Fuzhou 350008, Fujian, PR China.
³ School of Environmental Science & Engineering, North China Electric Power University, Baoding 071003, PR China. Electronic address: hrl_ncepu@hotmail.com.
⁴ Xiamen University, Xiamen 361000, Fujian, PR China; Jimei University, Fujian Province Key Laboratory of Energy Cleaning Utilization and Development, Xiamen 361021, Fujian, PR China.
⁵ School of Environmental Science & Engineering, North China Electric Power University, Baoding 071003, PR China.

PMID: 30059931
DOI: 10.1016/j.scitotenv.2018.07.286

Abstract

The combustion behaviors of anthracite and dried sawmill sludge (DSS) were studied using thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG). DSS was found to be a promoter for anthracite combustion, the addition of DSS in anthracite decreased the burnout temperature and time. But DSS caused the rapid releases of SO₂ and NO in the initial combustion stage. In overall, the increasing of DSS significantly decreased the emission factor of SO₂ from 13.42 ± 1.80 to 0.31 ± 0.08 g/kg; while the emission factor of NO was not obviously changed and stable at 0.7-0.8 g/kg in all cases. The oxygen-rich atmosphere was helpful for the rapid and sufficient combustion of blend; the oxygen-lean atmosphere delayed the combustion process and slowed down the releases of SO₂ and NO. The increasing combustion temperature improved the anthracite combustion, and the emission factors of SO₂ and NO were all increased with the temperature increasing. 900 °C was found to be the best combustion temperature for NO generation. SO₃ was detected in the combustion of anthracite under 21% and 30% of O₂. Two promising ways for control of SO₂ and NO were provided: 1) urea-fuel mixture combustion combined with the post-combustion wet absorption by Na₂CO₃; 2) post-combustion wet absorption by NaClO/Na₂CO₃. The removal efficiencies of SO₂ and NO could reach 100% and over 95% respectively. The removal products were determined as sulfate, sulfite and nitrate by IC, with no toxic byproducts being produced.

Keywords: Anthracite; Co-combustion; Emission factor; Flue gas cleaning; SO(2) and NO; Sludge.